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Privacy Policy

Last updated: April 7, 2026

Linea (“we”, “us”) operates readlinea.com, a reading app that helps language learners read real books with sentence-level translations and word-level alignments. This policy explains what personal data we collect, why we collect it, and what rights you have over it.

Who is the data controller?

Linea is the data controller for personal data processed through readlinea.com. You can contact us at privacy@readlinea.com.

What data we collect

  • Account information— your email address and, if you sign up with a password, a hashed password. If you sign in with Google, we receive your email address, name, and profile picture from Google.
  • Library and reading state— metadata about books you import (title, author, language, cover image, file hash), your reading progress, and your view preferences.
  • Book text you choose to translate— when you translate a page, the source text is sent to our translation and alignment providers. We cache translations so other users reading the same book don’t need to re-translate the same passages.
  • Vocabulary and knowledge data— words you encounter, look up, or hover over, and the familiarity scores Linea computes from those signals. This powers the adaptive translation fading.
  • Usage analytics— if you consent to analytics cookies, we collect anonymous usage data (pages viewed, features used, session duration) via PostHog. You can decline and Linea will work normally without it.
  • Error reports— when something breaks, we collect technical information about the error (stack trace, browser type, page URL) via Sentry to help us fix it.
  • Payment information— if you subscribe to a paid plan, Lemon Squeezy processes your payment. We receive your subscription status but never see your card details.

Legal basis for processing (GDPR)

If you are in the European Economic Area or the UK, we process your personal data on the following legal bases:

  • Performance of a contract— to provide the reading service you signed up for (authentication, storing your library, translating pages).
  • Legitimate interest— to keep the service secure, prevent abuse, and fix errors (Sentry).
  • Consent— for non-essential analytics cookies (PostHog). You can withdraw consent at any time without affecting the legality of prior processing.
  • Legal obligation— when we need to comply with applicable law (e.g. tax records for subscription payments).

How we use your data

  • Authenticate your account and maintain your session
  • Store your library, reading progress, and vocabulary across devices
  • Generate sentence translations, word alignments, and definitions via our AI providers
  • Fade translations for words you already know (the knowledge layer)
  • Monitor and debug errors so we can fix them
  • Understand how the product is used so we can improve it (only with your consent)
  • Process subscription payments and enforce quota limits

We do not sell your data or use it for advertising.

Subprocessors and third-party services

We share the minimum data necessary with the following service providers:

  • Supabase (United States) — authentication, PostgreSQL database, file storage for book covers
  • Vercel (United States) — web hosting and serverless functions
  • Groq (United States) — LLM provider for translation, word alignment, idiom detection, and word definitions. Source text you translate is sent to Groq’s API. Groq does not train on API data.
  • Upstash (United States) — Redis for rate limiting, quota tracking, and definition caching
  • Lemon Squeezy (United States) — payment processing for paid plans
  • PostHog (United States) — product analytics (only with your consent)
  • Sentry (United States) — error monitoring and crash reporting
  • Google (United States) — if you choose to sign in with Google, your authentication is handled by Google

International data transfers

All of the subprocessors listed above are based in or process data in the United States. If you are in the European Economic Area, the UK, or Switzerland, your personal data is transferred to the US. These transfers are protected by Standard Contractual Clauses and/or the EU-US Data Privacy Framework where applicable. You can request copies of the relevant safeguards by contacting us.

Data retention

  • Account data is kept for as long as your account exists. When you delete your account, your account record, library, reading state, and vocabulary data are permanently removed within 30 days.
  • Cached translations are retained indefinitely and shared across users reading the same book, because they are not personally identifiable once disconnected from your account.
  • Analytics and error data are retained according to the default retention periods of PostHog and Sentry (typically 7-90 days for raw events).
  • Payment records are retained for as long as required by tax law.

Your rights

Under GDPR and similar laws, you have the right to access, correct, delete, export, and restrict processing of your personal data, and to object to processing. You also have the right to lodge a complaint with your local data protection authority.

  • Access / export your data— download everything we store about you from Account Settings.
  • Delete your account— permanently remove your account and all associated data from Account Settings.
  • Withdraw analytics consent— clear your cookie choice in your browser, then reload the page to see the consent banner again.
  • Other requests — email privacy@readlinea.com and we will respond within 30 days.

Cookies and local storage

Linea uses two categories of browser storage:

  • Strictly necessary— authentication cookies from Supabase and local settings (theme, font preferences) in localStorage. These are required for Linea to function and do not require consent.
  • Analytics (optional)— PostHog stores an anonymous visitor ID in localStorage to measure usage. This is only enabled if you accept the analytics cookie banner.

Children

Linea is not directed at children under 16. We do not knowingly collect personal data from children under 16. If you believe a child has provided us with personal data, please contact us and we will delete it.

Changes to this policy

We may update this policy from time to time. When we make material changes, we will update the “Last updated” date and, for significant changes, notify you by email or an in-app notice.

Contact

If you have questions about this privacy policy or want to exercise your rights, email us at privacy@readlinea.com.